A method of controlling a non-return fuel supply system for an internal combustion engine

A non-return fuel supply system for an internal combustion engine operating with at least one cylinder (3) and comprising: at least one intake manifold (4) connected to the cylinder (3), at least one injector (5) for injecting fuel into the intake manifold (4), a fuel tank (6), a pump (7) substantially positioned in the tank (6) in order to deliver fuel to the injector (5), and a control station (9) comprising a first calculating unit adapted, for each injector (5), to calculate the value of the average pressure difference between the ends of the injector (5) during each injection phase, and a second calculating unit connected to the first calculating unit and adapted, for each injector (5), to calculate the average value of the flow rate of the injector (5) during each injection phase on the basis of the value of the average pressure difference between the ends of the injector (5) during the injection phase.